Interpolymer carboxylic membranes were prepared by the paste method. Transport of copper through the membrane was investigated by using a system containing HCl (receiver solution) and CuCl2 (feed solution). The transfer rate was found to be greatly affected by the membrane composition and HCl concentration in the receiver solution. A membrane based on poly(vinyl chloride)/poly(methyl methacrylate-co-divinylbenzene) with 5 wt % divinylbenzene showed the highest transfer rate.